feat: implement Stockable interface and methods for Bundle and ProductVariant models

app/Domains/Shared/Contracts/Stockable.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace App\Domains\Shared\Contracts;
+
+interface Stockable
+{
+    public function incrementRealStock(int $amount): void;
+    public function decrementRealStock(int $amount): void;
+    
+    public function incrementReservedStock(int $amount): void;
+    public function decrementReservedStock(int $amount): void;
+    public function confirmReservedStock(int $amount): void;
+    
+    public function validateStock(): void;
+}